Remove --{enable|disable}-orbit from configure.

[ahmedcharles]

Fixes #35956.

r? @eddyb

There are only two buildbots left, though they are both failing. Is there something to be done there other than wait?

[eddyb]

r=me once the no-mir builders are removed. I'm surprised buildbot hasn't been restarted.
cc @rust-lang/tools

[alexcrichton]

We don't really have a burning desire to do this, and restarting buildbot is pretty expensive, so it hasn't been done yet. I'll r+ this though once we've restarted buildbot at some point.

[eddyb]

Looks like buildbot was restarted.
@bors r+

[bors]

📌 Commit cd8f0aa has been approved by eddyb

[bors]

⌛ Testing commit cd8f0aa with merge b7d1989...

[bors]

☀️ Test successful - auto-linux-32-nopt-t, auto-linux-32-opt, auto-linux-64-cargotest, auto-linux-64-cross-freebsd, auto-linux-64-debug-opt, auto-linux-64-nopt-t, auto-linux-64-opt, auto-linux-64-opt-rustbuild, auto-linux-64-x-android-t, auto-linux-cross-opt, auto-linux-musl-64-opt, auto-mac-32-opt, auto-mac-64-opt, auto-mac-64-opt-rustbuild, auto-mac-cross-ios-opt, auto-win-gnu-32-opt, auto-win-gnu-32-opt-rustbuild, auto-win-gnu-64-opt, auto-win-msvc-32-opt, auto-win-msvc-64-cargotest, auto-win-msvc-64-opt, auto-win-msvc-64-opt-rustbuild
Approved by: eddyb
Pushing b7d1989 to master...